Answer:
The decimal point should be placed after the 0 in 45780. 
Step-by-step explanation:
 
        
             
        
        
        
Standard deviation I think
        
             
        
        
        
Answer:
B. 21.2
Step-by-step explanation:
Perimeter of ∆ABC = AB + BC + AC
A(-4, 1)
B(-2, 3)
C(3, -4)
✔️Distance between A(-4, 1) and B(-2, 3):




AB = 4 units
✔️Distance between B(-2, 3) and C(3, -4):




BC = 8.6 units (nearest tenth)
✔️Distance between A(-4, 1) and C(3, -4):




AC = 8.6 units (nearest tenth)
Perimeter of ∆ABC = 4 + 8.6 + 8.6 = 21.2 units
 
        
             
        
        
        
Transaction 3 - $143
transaction 4 - $-86
transaction 5 - $86
        
             
        
        
        
Point slope form follows the equation y-y₁=m(x-x₁), so we want it to look like that. Starting off with m, or the slope, we can find this using your two points with the formula 

. Note that y₁ and x₁ are from the same point, but it does not matter which point you designate to be point 1 and point 2. Thus, we can plug our numbers in - the x value comes first in the equation, and the y value comes second, so we have

 as our slope. Keeping in mind that it does not matter which point is point 1 and which point is point 2, we go back to  y-y₁=m(x-x₁) and plug a point in (I'll be using (10,5)). Note that x₁, m,  and y₁ need to be plugged in, but x and y stay that way so that you can plug x or y values into the formula to find where exactly it is on the line. Thus, we have our point slope equation to be 

Feel free to ask further questions!